The present invention relates to the field of inkjet printing and, in particular, discloses a High Young""s Modulus Thermoelastic Inkjet Printer.
Many different types of printing have been invented, a large number of which are presently in use. The known forms of print have a variety of methods for marking the print media with a relevant marking media. Commonly used forms of printing include offset printing, laser printing and copying devices, dot matrix type impact printers, thermal paper printers, film recorders, thermal wax printers, dye sublimation printers and ink jet printers both of the drop on demand and continuous flow type. Each type of printer has its own advantages and problems when considering cost, speed, quality, reliability, simplicity of construction and operation etc.
In recent years, the field of ink jet printing, wherein each individual pixel of ink is derived from one or more ink nozzles has become increasingly popular primarily due to its inexpensive and versatile nature.
Many different techniques on ink jet printing have been invented. For a survey of the field, reference is made to an article by J Moore, xe2x80x9cNon-Impact Printing: Introduction and Historical Perspectivexe2x80x9d, Output Hard Copy Devices, Editors R Dubeck and S Sherr, pages 207-220 (1988).
Ink Jet printers themselves come in many different types. The utilisation of a continuous stream of ink in ink jet printing appears to date back to at least 1929 wherein U.S. Pat. No. 1,941,001 by Hansell discloses a simple form of continuous stream electrostatic ink jet printing.
U.S. Pat. No. 3,596,275 by Sweet also discloses a process of a continuous ink jet printing including the step wherein the ink jet stream is modulated by a high frequency electrostatic field so as to cause drop separation. This technique is still utilized by several manufacturers including Elmjet and Scitex (see also U.S. Pat. No. 3,373,437 by Sweet et al) Piezo-electric ink jet printers are also one form of commonly utilized ink jet printing device. Piezo-electric systems are disclosed by Kyser et. al. in U.S. Pat. No. 3,946,398 (1970) which utilizes a diaphragm mode of operation, by Zolten in U.S. Pat. No. 3,683,212 (1970) which discloses a squeeze mode of operation of a piezo electric crystal, Stemme in U.S. Pat. No. 3,747,120 (1972) discloses a bend mode of piezo-electric operation, Howkins in U.S. Pat. No. 4,459,601 discloses a Piezo electric push mode actuation of the ink jet stream and Fischbeck in U.S. Pat. No. 4,584,590 which discloses a shear mode type of piezo-electric transducer element.
Recently, thermal ink jet printing has become an extremely popular form of ink jet printing. The ink jet printing techniques include those disclosed by Endo et al in GB 2007162 (1979) and Vaught et al in U.S. Pat. No. 4,490,728. Both the aforementioned references disclose ink jet printing techniques which rely upon the activation of an electrothermal actuator which results in the creation of a bubble in a constricted space, such as a nozzle, which thereby causes the ejection of ink from an aperture connected to the confined space onto a relevant print media. Printing devices utilizing the electro-thermal actuator are manufactured by manufacturers such as Canon and Hewlett Packard.
As can be seen from the foregoing, many different types of printing technologies are available. Ideally, a printing technology should have a number of desirable attributes. These include inexpensive construction and operation, high speed operation, safe and continuous long term operation etc. Each technology may have its own advantages and disadvantages in the areas of cost, speed, quality, reliability, power usage, simplicity of construction, operation, durability and consumables.
There is disclosed herein an ink jet nozzle assembly including a nozzle chamber having a nozzle through which ink from the chamber can be ejected, the chamber including a fixed portion and a movable portion configured for relative movement in an ejection phase and alternate relative movement in a refill phase, and an actuator connected with the movable portion and comprising materials having a Young""s modulus greater than about 200 GPa.
There is further disclosed herein an ink jet nozzle assembly including: a nozzle chamber having an inlet in fluid communication with an ink reservoir and a nozzle through which ink from the chamber can be ejected;
the chamber including a fixed portion and a movable portion configured for relative movement in an ejection phase and alternate relative movement in a refill phase;
a thermal actuator connected with the movable portion and comprising materials having a high Young""s modulus which produce a bending motion upon heating to effect periodically said relative movement; and
the inlet being positioned and dimensioned relative to the nozzle such that ink is ejected preferentially from the chamber through the nozzle in droplet form during the ejection phase, and ink is alternately drawn preferentially into the chamber from the reservoir through the inlet during the refill phase;
wherein the movable portion includes the nozzle and the fixed portion is mounted on a substrate.
Preferably the fixed portion includes the nozzle mounted on a substrate and the movable portion includes an ejection paddle.
Preferably said thermal actuator is pivoted so as to increase a degree of travel of said ejection paddle upon actuation of said thermal actuator.
Preferably said actuator is of a horse-shoe shape pivoted substantially about a midpoint thereof.
Preferably said midpoint is constructed on a wall of said chamber.
Preferably said wall comprises a thinned membrane.
Preferably said thermal actuator operates in an ambient atmosphere.
Preferably said nozzle chamber is constructed on a silicon wafer and said ink is supplied through said silicon wafer.
Preferably said thermal actuator is constructed from a thin conductive section and a substantially thicker non-conductive section.
Preferably said thin conductive section comprises substantially titanium diboride.
Preferably said thicker portion comprises substantially glass.
Preferably said nozzle chamber walls include a number of small sacrificial etchant holes to facilitate construction of said assembly, said holes being of a diameter sufficiently small so as to prevent an ejection of ink therethrough.
Preferably the assembly is manufactured using micro-electro-mechanical systems (MEMS) techniques.
Preferably an effective volume of the chamber is reduced in said ejection phase and enlarged in said refill phase.